Hemodynamic shear stress, the blood flow-generated frictional force acting on the vascular endothelial cells, is essential for endothelial homeostasis under normal physiological conditions. Mechanosensors on endothelial cells detect shear stress and transduce it into biochemical signals to trigger vascular adaptive responses. Among the various shear-induced signaling molecules, reactive oxygen species (ROS) and nitric oxide (NO) have been implicated in vascular homeostasis and diseases. In this review, we explore the molecular, cellular, and vascular processes arising from shear-induced signaling (mechanotransduction) with emphasis on the roles of ROS and NO, and also discuss the mechanisms that may lead to excessive vascular remodeling and thus drive pathobiologic processes responsible for atherosclerosis. Current evidence suggests that NADPH oxidase is one of main cellular sources of ROS generation in endothelial cells under flow condition. Flow patterns and magnitude of shear determine the amount of ROS produced by endothelial cells, usually an irregular flow pattern (disturbed or oscillatory) producing higher levels of ROS than a regular flow pattern (steady or pulsatile). ROS production is closely linked to NO generation and elevated levels of ROS lead to low NO bioavailability, as is often observed in endothelial cells exposed to irregular flow. The low NO bioavailability is partly caused by the reaction of ROS with NO to form peroxynitrite, a key molecule which may initiate many pro-atherogenic events. This differential production of ROS and RNS (reactive nitrogen species) under various flow patterns and conditions modulates endothelial gene expression and thus results in differential vascular responses. Moreover, ROS/RNS are able to promote specific post-translational modifications in regulatory proteins (including S-glutathionylation, S-nitrosylation and tyrosine nitration), which constitute chemical signals that are relevant in cardiovascular pathophysiology. Overall, the dynamic interplay between local hemodynamic milieu and the resulting oxidative and S-nitrosative modification of regulatory proteins is important for ensuing vascular homeostasis. Based on available evidence, it is proposed that a regular flow pattern produces lower levels of ROS and higher NO bioavailability, creating an anti-atherogenic environment. On the other hand, an irregular flow pattern results in higher levels of ROS and yet lower NO bioavailability, thus triggering pro-atherogenic effects.

This study developed an efficient and reliable system for inducing polyploidy in Anoectochilus formosanus Hayata, a top-grade medicinal orchid. The resulting tetraploid gave a significant enhancement on various agronomic traits, including dry weight, fresh weight, shoot length, root length, leaf width, the size of stoma, and number of chloroplasts per stoma. A reduction of the ratio of length to width was observed in stomata and leaves of the tetraploid, and consequently, an alteration of organ shape was found. The major bioactive compounds, total flavonoid and gastrodin, were determined by the aluminum chloride colorimetric method and ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), respectively. The tetraploid produced significantly higher contents of total flavonoid and gastrodin in the leaf, the stem, and the whole plant when compared with the diploid. The resulting tetraploids in this study are proposed to be suitable raw materials in the pharmaceutical industry for enhancing productivity and reducing cost.

Gynecologic tract melanoma is a malignant tumor with poor prognosis. Because of the low survival rate and the lack of a standard treatment protocol related to this condition, the investigation of the mechanisms underlying melanoma progression is crucial to achieve advancements in the relevant gynecological surgery and treatment. Mitochondrial transfer between adjacent cells in the tumor microenvironment regulates tumor progression. This study investigated the effects of endothelial mitochondria on the growth of melanoma cells and the activation of specific signal transduction pathways following mitochondrial transplantation. Mitochondria were isolated from endothelial cells (ECs) and transplanted into B16F10 melanoma cells, resulting in the upregulation of proteins associated with tumor growth. Furthermore, enhanced antioxidation and mitochondrial homeostasis mediated by the Sirt1-PGC-1α-Nrf2-HO-1 pathway were observed, along with the inhibition of apoptotic protein caspase-3. Finally, the transplantation of endothelial mitochondria into B16F10 cells promoted tumor growth and increased M2-type macrophages through Nrf2/HO-1-mediated pathways in a xenograft animal model. In summary, the introduction of exogenous mitochondria from ECs into melanoma cells promoted tumor growth, indicating the role of mitochondrial transfer by stromal cells in modulating a tumor’s phenotype. These results provide valuable insights into the role of mitochondrial transfer and provide potential targets for gynecological melanoma treatment.

Hydrogen sulfide (H₂S) and nitric oxide (NO), two endogenous gaseous molecules in endothelial cells, got increased attention with respect to their protective roles in the cardiovascular system. However, the details of the signaling pathways between H₂S and NO in endothelia cells remain unclear. In this study, a treatment with NaHS profoundly increased the expression and the activity of endothelial nitric oxide synthase. Elevated gaseous NO levels were observed by a novel and specific fluorescent probe, 5-amino-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid methyl ester (FA-OMe), and quantified by flow cytometry. Further study indicated an increase of upstream regulator for eNOS activation, AMP-activated protein kinase (AMPK), and protein kinase B (Akt). By using a biotin switch, the level of NO-mediated protein S-nitrosylation was also enhanced. However, with the addition of the NO donor, NOC-18, the expressions of cystathionine-γ-lyase, cystathionine-β-synthase, and 3-mercaptopyruvate sulfurtransferase were not changed. The level of H₂S was also monitored by a new designed fluorescent probe, 4-nitro-7-thiocyanatobenz-2-oxa-1,3-diazole (NBD-SCN) with high specificity. Therefore, NO did not reciprocally increase the expression of H₂S-generating enzymes and the H₂S level. The present study provides an integrated insight of cellular responses to H₂S and NO from protein expression to gaseous molecule generation, which indicates the upstream role of H₂S in modulating NO production and protein S-nitrosylation.

Background: The pleiotropic effects of 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), which are independent from their cholesterol-lowering action, have been widely recognized in various biological systems. Statins can affect endothelial homeostasis, which is partly modulated by the production of nitric oxide (NO). However, it is unclear how statin/NO-mediated posttranslational S-nitrosylation of endothelial proteins and changes in translational profiles may benefit endothelial integrity. Therefore, it is important to understand the statin/NO-mediated S-nitrosylation in endothelial cells. Results: Rosuvastatin treatment of human umbilical vein endothelial cells (ECs) enhanced the enzymatic activity of endothelial nitric oxide synthase (eNOS) and the expression of 78 S-nitrosoproteins. Among these S-nitrosoproteins, we identified 17 proteins, including protein disulfide bond isomerase, phospholipase C, transaldolase and heat shock proteins. Furthermore, a hydrophobic Cys66 was determined as the S-nitrosylation site of the mitochondrial HSP70. In addition to the statin-modulated posttranslational S-nitrosylation, changes in the NO-mediated translational proteome were also observed. Seventeen major proteins were significantly upregulated after rosuvastatin treatment. However, 12 of these proteins were downregulated after pretreating ECs with an eNOS inhibitor (L-NAME), which indicated that their expression was modulated by NO. Conclusions: ECs treated with rosuvastatin increase eNOS activation. The increased NO production is involved in modulating S-nitrosylation and translation of proteins. We provide further evidence of the pleiotropic effect of rosuvastatin on endothelial physiology.

Osteoarthritis (OA) is the most common joint disease characterized by degeneration of articular cartilage and causes severe joint pain, physical disability, and impaired quality of life. Recently, it was found that mitochondria not only act as a powerhouse of cells that provide energy for cellular metabolism, but are also involved in crucial pathways responsible for maintaining chondrocyte physiology. Therefore, a growing amount of evidence emphasizes that impairment of mitochondrial function is associated with OA pathogenesis; however, the exact mechanism is not well known. Moreover, the AMP-activated protein kinase (AMPK)–Sirtuin (SIRT) signaling pathway, long non-coding RNA (lncRNA), and microRNA (miRNA) are important for regulating the physiological and pathological processes of chondrocytes, indicating that these may be targets for OA treatment. In this review, we first focus on the importance of mitochondria metabolic dysregulation related to OA. Then, we show recent evidence on the AMPK-SIRT mediated pathway associated with OA pathogenesis and potential treatment options. Finally, we discuss current research into the effects of lncRNA and miRNA on OA progression or inhibition.